-// Copyright 2002 Adam Megacz, see the COPYING file for licensing [GPL]
+// Copyright 2003 Adam Megacz, see the COPYING file for licensing [GPL]
package org.xwt.js;
import org.xwt.util.*;
import java.io.*;
-
-/** parses a stream of lexed tokens into a tree of Expr's */
-public class Parser extends Lexer {
+/** parses a stream of lexed tokens into ForthBlock's */
+public class Parser extends Lexer implements OpCodes {
// Constructors //////////////////////////////////////////////////////
public static void main(String[] s) throws Exception {
Parser p = new Parser(new InputStreamReader(System.in), "stdin", 0);
while(true) {
- Expr block = p.parseBlock(false);
+ ForthBlock block = new ForthBlock(0, "stdin");
+ p.parseStatement(false, block);
if (block == null) return;
System.out.println(block);
if (p.peekToken() == -1) return;
static byte[] precedence = new byte[MAX_TOKEN + 1];
static boolean[] isRightAssociative = new boolean[MAX_TOKEN + 1];
static {
- precedence[ASSIGN] = 1;
isRightAssociative[ASSIGN] = true;
+
+ precedence[ASSIGN] = 1;
precedence[HOOK] = 2;
precedence[COMMA] = 3;
precedence[OR] = precedence[AND] = 4;
// Parsing Logic /////////////////////////////////////////////////////////
+ /** gets a token and throws an exception if it is not <tt>code</tt> */
public void consume(int code) throws IOException {
if (getToken() != code)
- throw new ParserException("expected " + codeToString[op] + ", got " + (op == -1 ? "EOL" : codeToString[op]));
+ throw new ParserException("expected " + codeToString[code] + ", got " + (op == -1 ? "EOL" : codeToString[op]));
}
- /** parses the largest possible expression */
- public Expr parseMaximalExpr() throws IOException { return parseMaximalExpr(null, -1); }
- public Expr parseMaximalExpr(Expr prefix, int minPrecedence) throws IOException {
- while(true) {
- if (peekToken() == -1) break;
- Expr save = prefix;
- prefix = parseSingleExpr(prefix, minPrecedence);
- if (save == prefix) break;
- if (prefix == null) throw new ParserException("parseSingleExpr() returned null");
- }
- return prefix;
- }
-
- public Expr parseSingleExpr(Expr prefix, int minPrecedence) throws IOException {
- Expr e1 = null, e2 = null, e3 = null, head = null, tail = null, ret = null;
+ /** append the largest expression beginning with prefix containing no operators of precedence below <tt>minPrecedence</tt> */
+ public ForthBlock startExpr() throws IOException { return startExpr(-1); }
+ public ForthBlock startExpr(int minPrecedence) throws IOException { return startExpr(minPrecedence, new ForthBlock(line, sourceName)); }
+ public ForthBlock startExpr(int minPrecedence, ForthBlock appendTo) throws IOException {
- int tok = peekToken();
- if (minPrecedence > 0 &&
- tok < precedence.length &&
- precedence[tok] != 0 &&
- (isRightAssociative[tok] ?
- (precedence[tok] < minPrecedence) :
- (precedence[tok] <= minPrecedence))) {
- return prefix;
- }
- getToken();
+ int tok = getToken();
int curLine = line;
+ if (tok == -1) return null;
+ if (minPrecedence > 0 && precedence[tok] != 0)
+ if (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok]))
+ { pushBackToken(); return null; }
- // these case arms match the precedence of operators; each arm is a precedence level.
- switch (tok) {
+ ForthBlock b = appendTo;
- case VAR: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ByteCode b = new ByteCode(curLine);
- b.add(b.THIS, NO_ARG);
+ switch (tok) {
+ case NUMBER: return continueExpr(b.add(ForthBlock.LITERAL, number), minPrecedence);
+ case STRING: return continueExpr(b.add(ForthBlock.LITERAL, string), minPrecedence);
+ case THIS: return continueExpr(b.add(THIS, null), minPrecedence);
+ case NULL: return continueExpr(b.add(ForthBlock.LITERAL, null), minPrecedence);
+ case TRUE: case FALSE: return continueExpr(b.add(ForthBlock.LITERAL, new Boolean(tok == TRUE)), minPrecedence);
+ case LB: {
+ b.add(b.ARRAY, new Integer(0));
+ int i = 0;
while(true) {
- consume(NAME);
- String name = string;
- b.add(b.DECLARE, name);
- if (peekToken() == ASSIGN) {
- b.add(b.LITERAL, name);
- consume(ASSIGN);
- b.add(b.EXPR, parseMaximalExpr());
- b.add(b.PUT, NO_ARG);
- b.add(b.POP, NO_ARG);
- }
- if (peekToken() != COMMA) break;
+ ForthBlock e = startExpr();
+ if (e == null && peekToken() == RB) { consume(RB); return continueExpr(b, minPrecedence); }
+ b.add(b.LITERAL, new Integer(i++));
+ if (e == null) b.add(b.LITERAL, null);
+ else b.add(b.EXPR, e);
+ b.add(b.PUT);
+ b.add(b.POP);
+ if (peekToken() == RB) { consume(RB); return continueExpr(b, minPrecedence); }
consume(COMMA);
}
- return b;
}
-
- case IN: pushBackToken(); return prefix;
-
- case IF: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ByteCode b = new ByteCode(curLine);
- consume(LP);
- b.add(b.EXPR, parseMaximalExpr());
- consume(RP);
- b.add(b.JF, new Integer(3));
- b.add(b.EXPR, parseBlock(false));
- b.add(b.JMP, new Integer(2));
- if (peekToken() != ELSE) return b.add(b.LITERAL, null);
- consume(ELSE);
- b.add(b.EXPR, parseBlock(false));
- return b;
- }
-
- // FIXME: ugly hack!!
- case ASSIGN_BITOR: if (tok == ASSIGN_BITOR) tok = BITOR;
- case ASSIGN_BITXOR: if (tok == ASSIGN_BITXOR) tok = BITXOR;
- case ASSIGN_BITAND: if (tok == ASSIGN_BITAND) tok = BITAND;
- case ASSIGN_LSH: if (tok == ASSIGN_LSH) tok = LSH;
- case ASSIGN_RSH: if (tok == ASSIGN_RSH) tok = RSH;
- case ASSIGN_URSH: if (tok == ASSIGN_URSH) tok = URSH;
- case ASSIGN_ADD: if (tok == ASSIGN_ADD) tok = ADD;
- case ASSIGN_SUB: if (tok == ASSIGN_SUB) tok = SUB;
- case ASSIGN_MUL: if (tok == ASSIGN_MUL) tok = MUL;
- case ASSIGN_DIV: if (tok == ASSIGN_DIV) tok = DIV;
- case ASSIGN_MOD: if (tok == ASSIGN_MOD) tok = MOD;
- {
- ByteCode b = (ByteCode)prefix;
- b.set(b.size() - 1, b.GET_PRESERVE, new Boolean(true));
- b.add(b.EXPR, parseMaximalExpr(null, precedence[tok]));
- b.add(tok, NO_ARG);
- b.add(b.PUT, NO_ARG);
- b.add(b.SWAP, NO_ARG);
- b.add(b.POP, NO_ARG);
- return b;
- }
-
- case INC: case DEC:
- if (prefix == null) {
- // prefix
- ByteCode b = (ByteCode)parseMaximalExpr(null, precedence[tok]);
- b.set(b.size() - 1, tok, new Boolean(true));
- return b;
- } else {
- // postfix
- ByteCode b = (ByteCode)prefix;
- b.set(b.size() - 1, tok, new Boolean(false));
- return b;
- }
-
- case LP:
- if (prefix == null) { // grouping
- ByteCode b = new ByteCode(curLine, ByteCode.EXPR, parseMaximalExpr());
- consume(RP);
- return b;
-
- } else { // invocation
- ByteCode b = new ByteCode(curLine);
- int i = 0;
- b.add(b.EXPR, prefix);
- while(peekToken() != RP) {
- b.add(b.EXPR, parseMaximalExpr());
- i++;
- if (peekToken() == RP) break;
- consume(COMMA);
- }
- consume(RP);
- b.add(b.CALL, new Integer(i));
- return b;
- }
-
- case BANG: case BITNOT: case INSTANCEOF: case TYPEOF: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ByteCode b = new ByteCode(curLine);
- b.add(b.EXPR, parseMaximalExpr(null, precedence[tok]));
- b.add(tok, NO_ARG);
- return b;
- }
-
- case SUB:
- if (prefix == null && peekToken() == NUMBER) {
- getToken();
- return new ByteCode(curLine, ByteCode.LITERAL, new Double(number.doubleValue() * -1));
- } // else fall through
- case BITOR: case BITXOR: case BITAND: case SHEQ: case SHNE: case LSH:
- case RSH: case URSH: case ADD: case MUL: case DIV: case MOD:
- case GT: case GE: case EQ: case NE: case LT: case LE: {
- if (prefix == null) throw new ParserException("the " + codeToString[tok] + " token cannot start an expression");
- ByteCode b = new ByteCode(curLine);
- b.add(b.EXPR, prefix);
- b.add(b.EXPR, parseMaximalExpr(null, precedence[tok]));
- b.add(tok, NO_ARG);
- return b;
+ case SUB: {
+ consume(NUMBER);
+ return continueExpr(b.add(ForthBlock.LITERAL, new Double(number.doubleValue() * -1)), minPrecedence);
}
-
- // includes short-circuit logic
- case OR: case AND: {
- if (prefix == null) throw new ParserException("the " + codeToString[tok] + " token cannot start an expression");
- ByteCode b = new ByteCode(curLine);
- b.add(b.LITERAL, tok == AND ? new Boolean(false) : new Boolean(true));
- b.add(b.EXPR, prefix);
- b.add(tok == AND ? b.JF : b.JT, new Integer(3));
- b.add(b.POP, NO_ARG);
- b.add(b.EXPR, parseMaximalExpr(null, precedence[tok]));
- return b;
- }
-
- case ASSIGN: {
- if (prefix == null) throw new ParserException("the " + codeToString[tok] + " token cannot start an expression");
- ByteCode b = new ByteCode(curLine);
- b.add(b.THIS, NO_ARG);
- b.add(b.LITERAL, prefix.string); // FIXME, this is ass-ugly
- b.add(b.EXPR, parseMaximalExpr(null, precedence[ASSIGN]));
- b.add(b.PUT, NO_ARG);
- b.add(b.SWAP, NO_ARG);
- b.add(b.POP, NO_ARG);
- return b;
- }
-
- case WITH: throw new ParserException("XWT does not allow the WITH keyword");
- case VOID: case RESERVED: throw new ParserException("reserved word that you shouldn't be using");
-
- case NUMBER:
- if (prefix != null) { pushBackToken(); return prefix; }
- return new ByteCode(curLine, ByteCode.LITERAL, number);
-
- case STRING:
- if (prefix != null) { pushBackToken(); return prefix; }
- return new ByteCode(curLine, ByteCode.LITERAL, string);
-
- case NULL: case TRUE: case FALSE: case NOP:
- if (prefix != null) { pushBackToken(); return prefix; }
- return new ByteCode(curLine, ByteCode.LITERAL, (tok == NULL || tok == NOP) ? null : new Boolean(tok == TRUE));
-
- case COMMA: pushBackToken(); return prefix;
-
- case THIS:
- if (prefix != null) { pushBackToken(); return prefix; }
- return new ByteCode(curLine, ByteCode.THIS, NO_ARG);
-
- // potential lvalues
-
- case NAME: {
- if (prefix != null) { pushBackToken(); return prefix; }
- String name = string;
- ByteCode b = new ByteCode(curLine);
- if (peekToken() == ASSIGN) {
- consume(ASSIGN);
- b.add(ByteCode.THIS, NO_ARG);
- b.add(ByteCode.LITERAL, name);
- b.add(ByteCode.EXPR, parseMaximalExpr(null, minPrecedence));
- b.add(ByteCode.PUT, NO_ARG);
- b.add(ByteCode.SWAP, NO_ARG);
- b.add(ByteCode.POP, NO_ARG);
- return b;
- } else {
- b.add(ByteCode.THIS, NO_ARG);
- b.add(ByteCode.LITERAL, name);
- b.add(ByteCode.GET, NO_ARG);
- return parseMaximalExpr(b, minPrecedence);
- }
+ case LP: {
+ b.add(EXPR, startExpr());
+ consume(RP);
+ return continueExpr(b, minPrecedence);
}
-
- case DOT: {
- consume(NAME);
- String target = string;
- ByteCode b = new ByteCode(curLine);
- b.add(b.EXPR, prefix);
- if (peekToken() == ASSIGN) {
- consume(ASSIGN);
- Expr val = parseMaximalExpr();
- b.add(b.LITERAL, target);
- b.add(b.EXPR, val);
- b.add(b.PUT, NO_ARG);
- b.add(b.SWAP, NO_ARG);
- b.add(b.POP, NO_ARG);
- } else {
- b.add(b.LITERAL, target);
- b.add(b.GET, NO_ARG);
- }
- return b;
+ case INC: case DEC: {
+ // prefix
+ ForthBlock subexp = startExpr(precedence[tok]);
+ subexp.set(subexp.size() - 1, tok, new Boolean(true));
+ b.add(b.EXPR, subexp);
+ return continueExpr(b, minPrecedence);
}
-
- case LB: {
- ByteCode b = new ByteCode(curLine);
- if (prefix == null) {
- b.add(b.ARRAY, new Integer(0));
- int i = 0;
- while(true) {
- Expr e = parseMaximalExpr();
- if (e == null && peekToken() == RB) { consume(RB); return b; }
- b.add(b.LITERAL, new Integer(i++));
- if (e == null) b.add(b.LITERAL, null);
- else b.add(b.EXPR, e);
- b.add(b.PUT, NO_ARG);
- b.add(b.POP, NO_ARG);
- if (peekToken() == RB) { consume(RB); return b; }
- consume(COMMA);
- }
- } else {
- b.add(b.EXPR, prefix);
- b.add(b.EXPR, parseMaximalExpr());
- consume(RB);
- if (peekToken() == ASSIGN) {
- consume(ASSIGN);
- b.add(b.EXPR, parseMaximalExpr());
- b.add(b.PUT, NO_ARG);
- b.add(b.SWAP, NO_ARG);
- b.add(b.POP, NO_ARG);
- } else {
- b.add(b.GET, NO_ARG);
- }
- return b;
- }
+ case BANG: case BITNOT: case INSTANCEOF: case TYPEOF: {
+ b.add(b.EXPR, startExpr(precedence[tok]));
+ b.add(tok);
+ return continueExpr(b, minPrecedence);
}
-
case LC: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ByteCode b = new ByteCode(curLine);
b.add(b.OBJECT, null);
- if (peekToken() == RC) { consume(RC); return b; }
+ if (peekToken() == RC) { consume(RC); return continueExpr(b, minPrecedence); }
while(true) {
if (peekToken() != NAME && peekToken() != STRING) throw new Error("expected NAME or STRING");
getToken();
b.add(b.LITERAL, string);
consume(COLON);
- b.add(b.EXPR, parseMaximalExpr());
- b.add(b.PUT, NO_ARG);
- b.add(b.POP, NO_ARG);
- if (peekToken() == RC) { consume(RC); return b; }
+ b.add(b.EXPR, startExpr());
+ b.add(b.PUT);
+ b.add(b.POP);
+ if (peekToken() == RC) { consume(RC); return continueExpr(b, minPrecedence); }
consume(COMMA);
- if (peekToken() == RC) { consume(RC); return b; }
+ if (peekToken() == RC) { consume(RC); return continueExpr(b, minPrecedence); }
}
}
-
- case HOOK: {
- ByteCode b = new ByteCode(curLine);
- b.add(b.EXPR, prefix);
- b.add(b.JF, new Integer(3));
- b.add(b.EXPR, parseMaximalExpr());
- b.add(b.JMP, new Integer(2));
- consume(COLON);
- b.add(b.EXPR, parseMaximalExpr());
- return b;
+ case NAME: {
+ String name = string;
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ b.add(THIS);
+ b.add(ForthBlock.LITERAL, name);
+ b.add(ForthBlock.EXPR, startExpr(minPrecedence));
+ b.add(ForthBlock.PUT);
+ b.add(ForthBlock.SWAP);
+ b.add(ForthBlock.POP);
+ } else {
+ b.add(THIS);
+ b.add(ForthBlock.LITERAL, name);
+ b.add(ForthBlock.GET);
+ }
+ return continueExpr(b, minPrecedence);
}
-
- case FUNCTION: {
- if (prefix != null) { pushBackToken(); return prefix; }
+ case Tokens.FUNCTION: {
consume(LP);
- ByteCode b = new ByteCode(curLine);
int numArgs = 0;
- b.add(b.THIS, NO_ARG);
- b.add(b.SWAP, NO_ARG);
- b.add(b.LITERAL, "arguments");
- b.add(b.LITERAL, "arguments");
- b.add(b.DECLARE, NO_ARG);
- b.add(b.SWAP, NO_ARG);
- b.add(b.PUT, NO_ARG);
- b.add(b.SWAP, NO_ARG);
- b.add(b.POP, NO_ARG);
+ ForthBlock b2 = new ForthBlock(curLine, sourceName);
+ b2.add(THIS);
+ b2.add(b.SWAP);
+ b2.add(b.LITERAL, "arguments");
+ b2.add(b.LITERAL, "arguments");
+ b2.add(b.DECLARE);
+ b2.add(b.SWAP);
+ b2.add(b.PUT);
+ b2.add(b.SWAP);
+ b2.add(b.POP);
if (peekToken() == RP) consume(RP);
else while(true) {
if (peekToken() == COMMA) {
+ // FIXME: pop an item off the stack here?
consume(COMMA);
} else {
consume(NAME);
// declare the name
- b.add(b.LITERAL, string);
- b.add(b.DECLARE, NO_ARG);
+ b2.add(b.LITERAL, string);
+ b2.add(b.DECLARE);
// retrieve it from the arguments array
- b.add(b.LITERAL, new Integer(numArgs));
- b.add(b.GET_PRESERVE, NO_ARG);
- b.add(b.SWAP, NO_ARG);
- b.add(b.POP, NO_ARG);
+ b2.add(b.LITERAL, new Integer(numArgs));
+ b2.add(b.GET_PRESERVE);
+ b2.add(b.SWAP);
+ b2.add(b.POP);
// put it to the current scope
- b.add(b.THIS, NO_ARG);
- b.add(b.SWAP, NO_ARG);
- b.add(b.LITERAL, string);
- b.add(b.SWAP, NO_ARG);
- b.add(b.PUT, NO_ARG);
+ b2.add(THIS);
+ b2.add(b.SWAP);
+ b2.add(b.LITERAL, string);
+ b2.add(b.SWAP);
+ b2.add(b.PUT);
// clean the stack
- b.add(b.POP, NO_ARG);
- b.add(b.POP, NO_ARG);
+ b2.add(b.POP);
+ b2.add(b.POP);
if (peekToken() == RP) { consume(RP); break; }
consume(COMMA);
numArgs++;
}
// pop off the arguments array
- b.add(b.POP, NO_ARG);
- parseBlock(true, b);
- return new ByteCode(curLine, b.FUNCTION, b);
- }
-
- case WHILE: {
- if (prefix != null) { pushBackToken(); return prefix; }
- consume(LP);
- ByteCode r = new ByteCode(curLine);
- ByteCode loop = new ByteCode(curLine);
- r.add(loop.LOOP, loop);
- r.add(r.LITERAL, null);
-
- loop.add(loop.EXPR, parseMaximalExpr());
- loop.add(loop.JT, new Integer(2));
- loop.add(Lexer.BREAK, NO_ARG);
- consume(RP);
- parseBlock(false, loop);
-
- // if we fall out of the end, definately continue
- loop.add(CONTINUE, NO_ARG);
- return r;
- }
-
- case SWITCH: {
- if (prefix != null) { pushBackToken(); return prefix; }
- consume(LP);
- ByteCode r = new ByteCode(curLine);
- ByteCode loop = new ByteCode(curLine);
- r.add(loop.LOOP, loop);
- r.add(r.LITERAL, null);
- loop.add(loop.EXPR, parseMaximalExpr());
- consume(RP);
- consume(LC);
- while(true) {
- Expr caseExpr;
- tok = getToken();
- if (tok == CASE) {
- loop.add(loop.DUP, NO_ARG);
- loop.add(loop.EXPR, parseMaximalExpr());
- loop.add(EQ, NO_ARG);
- loop.add(loop.JF, new Integer(2));
- } else if (tok != DEFAULT) throw new ParserException("expected CASE or DEFAULT");
- consume(COLON);
- ByteCode b = new ByteCode(curLine);
- while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
- if ((e1 = parseBlock(false)) == null) break;
- b.add(b.EXPR, e1);
- }
- loop.add(loop.EXPR, b);
- if (peekToken() == RC) {
- consume(RC);
- r.add(BREAK, NO_ARG);
- return r;
- }
- }
- }
-
- case DO: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ByteCode r = new ByteCode(curLine);
- ByteCode loop = new ByteCode(curLine);
- r.add(loop.LOOP, loop);
- r.add(r.LITERAL, null);
-
- parseBlock(false, loop);
- consume(WHILE);
- consume(LP);
- loop.add(loop.EXPR, parseMaximalExpr());
- loop.add(loop.JT, new Integer(2));
- loop.add(Lexer.BREAK, NO_ARG);
- loop.add(Lexer.CONTINUE, NO_ARG);
- consume(RP);
- consume(SEMI);
- return r;
- }
-
- // Needs break //
-
- case FOR:
- if (prefix != null) { pushBackToken(); return prefix; }
- if (getToken() != LP) throw new ParserException("expected left paren");
- e1 = parseMaximalExpr();
- if (peekToken() == IN) {
- getToken();
- e2 = parseMaximalExpr();
- if (getToken() != RP) throw new ParserException("expected right paren");
- return new Expr(curLine, FOR, new Expr(curLine, IN, e1.left, e2), parseBlock(false));
-
- } else {
- Expr initExpr = e1;
- if (initExpr == null) initExpr = new Expr(curLine, NULL);
- consume(SEMI);
- Expr whileExpr = parseMaximalExpr();
- consume(SEMI);
- Expr incExpr = parseMaximalExpr();
- consume(RP);
- Expr body = parseBlock(false);
- Expr loop = new Expr(curLine, WHILE, whileExpr, body);
- ExprList list = new ExprList(curLine, LC);
- list.add(initExpr);
- ExprList list2 = new ExprList(curLine, WHILE);
- list.add(list2);
- list2.add(whileExpr);
- list2.add(body);
- list2.add(incExpr);
- return list;
- }
-
- case TRY: {
- // We deliberately allow you to omit braces in catch{}/finally{} if they are single statements...
- if (prefix != null) { pushBackToken(); return prefix; }
- Expr tryBlock = parseBlock(true);
-
- tok = peekToken();
- ExprList list = new ExprList(curLine, TRY);
- if (tok == CATCH) {
- getToken();
- if (getToken() != LP) throw new ParserException("expected (");
- if (getToken() != NAME) throw new ParserException("expected name");
- Expr name = new Expr(curLine, NAME, string);
- if (getToken() != RP) throw new ParserException("expected )");
- list.add(new Expr(curLine, CATCH, name, parseBlock(false)));
- tok = peekToken();
- }
- if (tok == FINALLY) {
- getToken();
- list.add(new Expr(curLine, FINALLY, parseBlock(false)));
- }
-
- if (list.size() == 0) throw new ParserException("try without catch or finally");
- return new Expr(curLine, TRY, tryBlock, list);
+ b2.add(b.POP);
+ parseStatement(true, b2);
+ b2.add(b.LITERAL, null);
+ b2.add(RETURN);
+ return continueExpr(b.add(OpCodes.FUNCTION, b2), minPrecedence);
}
-
- default:
- pushBackToken();
- return prefix;
+ default: pushBackToken(); return null;
}
}
-
- // Expr //////////////////////////////////////////////////////////////////////
-
- public static final Object NO_ARG = new Object();
-
- class ByteCode extends Expr {
- // This class interprets a small forthlike bytecode language
- // we use to represent JavaScript. It's a stack machine.
- // Each instruction is an opcode and a literal. Any operation
- // that accesses the top of the stack and does not have a
- // mandatory literal can be performed on a literal instead of
- // the top of the stack.
-
- // opcodes:
- public static final byte arithmetic = -1; // -- arithmetic operators from parser
- public static final byte LITERAL = -2; // < String | Number | null > -- push a literal onto the stack
- public static final byte ARRAY = -3; // < size > -- create a new array of size <size>
- public static final byte OBJECT = -4; // -- push an empty object onto the stack
- public static final byte FUNCTION = -5; // < bytecode_block > -- push a new instance of a function with the given bytecode
- public static final byte DECLARE = -6; // < name > -- declare <name> in the current scope
- public static final byte THIS = -7; // -- push the topmost non-transparent scope onto the stack
- public static final byte GET = -8; // -- get stack[0] from stack[1]
- public static final byte GET_PRESERVE = -80; // -- get stack[0] from stack[1]
- public static final byte PUT = -9; // -- put stack[1] to key stack[0] on stack[2]; leaves object on the stack
- public static final byte THROW = -10; // -- throw topmost element
- public static final byte RETURN = -11; // -- return the topmost value on the stack
- public static final byte ASSERT = -12; // -- fail if topmost element is not true
- public static final byte JT = -13; // < relative_address > -- pop the stack; if true, jump to <relative_address>
- public static final byte JF = -21; // < relative_address > -- pop the stack; if false, jump to <relative_address>
- public static final byte JMP = -22; // < relative_address > -- jump to <relative_address>
- static public final byte POP = -14; // -- discard the top element on the stack
-
- public static final byte CALL = -15; // < numargs > -- call stack[0] with the topmost <numargs> values as arguments
- public static final byte TRY = -16; // < bytecode_block > -- run the block pointed to; returns with thrown exn on top of stack
+ /** return the largest expression beginning with prefix containing no operators of precedence below <tt>minPrecedence</tt> */
+ public ForthBlock continueExpr(ForthBlock prefix, int minPrecedence) throws IOException {
+ return continueExpr(prefix, minPrecedence, new ForthBlock(line, sourceName));
+ }
+ public ForthBlock continueExpr(ForthBlock prefix, int minPrecedence, ForthBlock appendTo) throws IOException {
+ int tok = getToken();
+ int curLine = line;
+ if (tok == -1) return prefix;
+ if (minPrecedence > 0 && precedence[tok] != 0)
+ if (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok]))
+ { pushBackToken(); return prefix; }
- public static final byte INSTANCEOF = -17; // -- ??
- public static final byte TYPEOF = -18; // --
+ if (prefix == null) throw new Error("got null prefix");
- public static final byte FOR__IN = -19; // -- ??
- public static final byte EXPR = -20; // -- transitional
- public static final byte SWAP = -23; // -- transitional
- public static final byte SCOPE = -30; // -- transitional
- public static final byte LOOP = -40; // -- transitional
- public static final byte DUP = -50; // -- transitional
+ ForthBlock b = appendTo;
- int[] op = new int[10];
- Object[] arg = new Object[10];
- int size = 0;
+ switch (tok) {
- public ByteCode(int line) { super(line, "foo"); }
- public ByteCode(int line, int op_, Object arg_) { this(line); add(op_, arg_); }
+ case ASSIGN_BITOR: case ASSIGN_BITXOR: case ASSIGN_BITAND: case ASSIGN_LSH: case ASSIGN_RSH: case ASSIGN_URSH:
+ case ASSIGN_ADD: case ASSIGN_SUB: case ASSIGN_MUL: case ASSIGN_DIV: case ASSIGN_MOD: {
+ b.add(b.EXPR, prefix);
+ prefix.set(prefix.size() - 1, b.GET_PRESERVE, new Boolean(true));
+ prefix.add(prefix.EXPR, startExpr(precedence[tok - 1]));
+ prefix.add(tok - 1);
+ prefix.add(b.PUT);
+ prefix.add(b.SWAP);
+ prefix.add(b.POP);
+ return continueExpr(b, minPrecedence);
+ }
+
+ case INC: case DEC: {
+ // postfix
+ prefix.set(prefix.size() - 1, tok, new Boolean(false));
+ b.add(b.EXPR, prefix);
+ return continueExpr(b, minPrecedence);
+ }
- public int size() { return size; }
- public void set(int pos, int op_, Object arg_) { op[pos] = op_; arg[pos] = arg_; }
- public ByteCode add(int op_, Object arg_) {
- if (size == op.length - 1) {
- int[] op2 = new int[op.length * 2]; System.arraycopy(op, 0, op2, 0, op.length); op = op2;
- Object[] arg2 = new Object[op.length * 2]; System.arraycopy(arg, 0, arg2, 0, arg.length); arg = arg2;
+ case LP: {
+ // invocation
+ int i = 0;
+ b.add(b.EXPR, prefix);
+ while(peekToken() != RP) {
+ b.add(b.EXPR, startExpr());
+ i++;
+ if (peekToken() == RP) break;
+ consume(COMMA);
}
- op[size] = op_;
- arg[size] = arg_;
- size++;
- return this;
- }
-
- public Object eval(final JS.Scope s) throws ControlTransferException, JS.Exn {
- return eval(s, new Parser.Thread());
+ consume(RP);
+ b.add(b.CALL, new Integer(i));
+ return continueExpr(b, minPrecedence);
}
- public Object eval(final JS.Scope s, Parser.Thread t) throws ControlTransferException {
- for(int i=0; i<size; i++)
- switch(op[i]) {
- case arithmetic: break;
- case LITERAL:
- t.push(arg[i]);
- break;
- case OBJECT: t.push(new JS.Obj()); break;
- case ARRAY: t.push(new JS.Array(toNumber(arg[i]).intValue())); break;
- case DECLARE: s.declare(arg[i] == NO_ARG ? (String)t.pop() : (String)arg[i]); break;
- case THIS: t.push(s); break; // FIXME: transparents
- case ASSERT: if (!toBoolean(t.pop())) throw new EvaluatorException("assertion failed"); break;
- case THROW: throw new JS.Exn(t.pop());
- case JT: if (toBoolean(t.pop())) i += toNumber(arg[i]).intValue() - 1; break;
- case JF: if (!toBoolean(t.pop())) i += toNumber(arg[i]).intValue() - 1; break;
- case JMP: i += toNumber(arg[i]).intValue() - 1; break;
- case POP: t.pop(); break;
- case SWAP: t.swap(); break;
- case DUP: t.push(t.peek()); break;
-
- case Lexer.BREAK: {
- // FIXME: make sure this can only appear in proper places
- return Boolean.FALSE;
- }
- case Lexer.CONTINUE: {
- // FIXME: make sure this can only appear in proper places
- return Boolean.TRUE;
- }
- case LOOP: {
- ByteCode loop = (ByteCode)arg[i];
- Parser.Thread t2 = new Parser.Thread();
- t2.push(Boolean.TRUE);
- while (true) {
- Boolean result;
- try {
- result = (Boolean)loop.eval(new JS.Scope(s), t2);
- } catch (ContinueException c) {
- result = Boolean.TRUE;
- } catch (BreakException b) {
- result = Boolean.FALSE;
- }
- if (result == Boolean.FALSE) break;
- t2 = new Parser.Thread();
- t2.push(Boolean.FALSE);
- }
- break;
- }
-
- case PUT: {
- Object val = arg[i] == NO_ARG ? t.pop() : arg[i];
- Object key = t.pop();
- ((JS)t.peek()).put(key, val);
- t.push(val);
- break;
- }
- case GET: {
- Object v = arg[i] == NO_ARG ? t.pop() : arg[i];
- Object o = t.pop();
- t.push(doGet(o, v));
- break;
- }
- case GET_PRESERVE: {
- Object v = t.pop();
- Object o = t.peek();
- t.push(v);
- t.push(doGet(o, v));
- break;
- }
- case NOP: break;
-
- case EXPR: t.push(((Expr)arg[i]).eval(s)); break;
- case SCOPE: t.push(((Expr)arg[i]).eval(new JS.Scope(s))); break;
-
- case CALL:
- JS.Array arguments = new JS.Array();
- int numArgs = toNumber(arg[i]).intValue();
- arguments.setSize(numArgs);
- for(int j=numArgs - 1; j >= 0; j--) arguments.setElementAt(t.pop(), j);
- JS.Function f = (JS.Function)t.pop();
- if (f == null) throw new JS.Exn(new EvaluatorException("attempted to call null"));
- t.push(f.call(arguments));
- break;
-
- case FUNCTION: {
- final ByteCode myBytes = (ByteCode)arg[i];
- t.push(new JS.Function() {
- public String toString() { return sourceName + ":" + line; }
- public String getSourceName() throws JS.Exn { return sourceName; }
- public Object _call(final JS.Array args) throws JS.Exn {
- Function save = JS.getCurrentFunction();
- JS.currentFunction.put(java.lang.Thread.currentThread(), this);
- JS.Scope scope = new JS.Scope(s) {
- // FIXME
- public String getSourceName() { return sourceName; }
- public Object get(Object key) throws JS.Exn {
- if (key.equals("trapee")) return org.xwt.Trap.currentTrapee();
- else if (key.equals("cascade")) return org.xwt.Trap.cascadeFunction;
- return super.get(key);
- }
- };
- Parser.Thread t0 = new Parser.Thread();
- t0.push(args);
- try {
- return myBytes.eval(scope, t0);
- } catch (ReturnException r) {
- return r.retval;
- } catch (ControlTransferException c) {
- throw new EvaluatorException("error, ControlTransferException tried to leave a function: " + c);
- } finally {
- if (save == null) JS.currentFunction.remove(java.lang.Thread.currentThread());
- else JS.currentFunction.put(java.lang.Thread.currentThread(), save);
- }
- }
- });
- break;
- }
-
- case RETURN: break;
- case TRY: break;
- case INSTANCEOF: break;
- case TYPEOF: break;
- case FOR__IN: break;
-
- case Lexer.BITNOT: t.push(new Long(~toLong(t.pop()))); break;
- case Lexer.BANG: t.push(new Boolean(!toBoolean(t.pop()))); break;
-
- case Lexer.INC: case Lexer.DEC: {
- boolean isPrefix = toBoolean(arg[i]);
- Object key = t.pop();
- JS obj = (JS)t.pop();
- Number num = toNumber(obj.get(key));
- Number val = new Double(op[i] == Lexer.INC ? num.doubleValue() + 1.0 : num.doubleValue() - 1.0);
- obj.put(key, val);
- t.push(isPrefix ? val : num);
- break;
- }
-
- default: {
- Object right = t.pop();
- Object left = t.pop();
- switch(op[i]) {
-
- case Lexer.BITOR: t.push(new Long(toLong(left) | toLong(right))); break;
- case Lexer.BITXOR: t.push(new Long(toLong(left) ^ toLong(right))); break;
- case Lexer.BITAND: t.push(new Long(toLong(left) & toLong(right))); break;
+ case BITOR: case BITXOR: case BITAND: case SHEQ: case SHNE: case LSH:
+ case RSH: case URSH: case ADD: case MUL: case DIV: case MOD:
+ case GT: case GE: case EQ: case NE: case LT: case LE: case SUB: {
+ b.add(b.EXPR, prefix);
+ b.add(b.EXPR, startExpr(precedence[tok]));
+ b.add(tok);
+ return continueExpr(b, minPrecedence);
+ }
- case Lexer.ADD: {
- Object l = left;
- Object r = right;
- if (l instanceof String || r instanceof String) {
- if (l == null) l = "null";
- if (r == null) r = "null";
- if (l instanceof Number && ((Number)l).doubleValue() == ((Number)l).longValue())
- l = new Long(((Number)l).longValue());
- if (r instanceof Number && ((Number)r).doubleValue() == ((Number)r).longValue())
- r = new Long(((Number)r).longValue());
- t.push(l.toString() + r.toString()); break;
- }
- t.push(new Double(toDouble(l) + toDouble(r))); break;
- }
-
- case Lexer.SUB: t.push(new Double(toDouble(left) - toDouble(right))); break;
- case Lexer.MUL: t.push(new Double(toDouble(left) * toDouble(right))); break;
- case Lexer.DIV: t.push(new Double(toDouble(left) / toDouble(right))); break;
- case Lexer.MOD: t.push(new Double(toDouble(left) % toDouble(right))); break;
-
- case Lexer.LSH: t.push(new Long(toLong(left) << toLong(right))); break;
- case Lexer.RSH: t.push(new Long(toLong(left) >> toLong(right))); break;
- case Lexer.URSH: t.push(new Long(toLong(left) >>> toLong(right))); break;
-
- // FIXME: these need to work on strings
- case Lexer.LT: t.push(toDouble(left) < toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
- case Lexer.LE: t.push(toDouble(left) <= toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
- case Lexer.GT: t.push(toDouble(left) > toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
- case Lexer.GE: t.push(toDouble(left) >= toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
-
- case Lexer.EQ:
- case Lexer.NE: {
- // FIXME: should use Javascript coercion-equality rules
- Object l = left;
- Object r = right;
- boolean ret;
- if (l == null) { Object tmp = r; r = l; l = tmp; }
- if (l == null && r == null) ret = true;
- else if (l instanceof Boolean) ret = new Boolean(toBoolean(r)).equals(l);
- else if (l instanceof Number) ret = toNumber(r).doubleValue() == toNumber(l).doubleValue();
- else if (l instanceof String) ret = r != null && l.equals(r.toString());
- else ret = l.equals(r);
- t.push(new Boolean(op[i] == Lexer.EQ ? ret : !ret)); break;
- }
+ case OR: case AND: {
+ b.add(b.LITERAL, tok == AND ? new Boolean(false) : new Boolean(true));
+ b.add(b.EXPR, prefix);
+ b.add(tok == AND ? b.JF : b.JT, new Integer(3));
+ b.add(b.POP);
+ b.add(b.EXPR, startExpr(precedence[tok]));
+ return continueExpr(b, minPrecedence);
+ }
- default: throw new Error("unknown opcode " + op[i]);
- } }
- }
- if (t.size() != 1) {
- throw new EvaluatorException("eval() terminated with " + t.size() + " elements on the stack; one expected");
+ case DOT: {
+ consume(NAME);
+ String target = string;
+ b.add(b.EXPR, prefix);
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ ForthBlock val = startExpr();
+ b.add(b.LITERAL, target);
+ b.add(b.EXPR, val);
+ b.add(b.PUT);
+ b.add(b.SWAP);
+ b.add(b.POP);
+ } else {
+ b.add(b.LITERAL, target);
+ b.add(b.GET);
}
- return t.pop();
+ return continueExpr(b, minPrecedence);
}
- public Object doGet(final Object o, final Object v) {
- if (o == null) throw new EvaluatorException("tried to get property \"" + v + "\" from the null value");
- if (o instanceof String) {
- if (v.equals("length")) return new Integer(((String)o).length());
- else if (v.equals("substring")) return new JS.Function() {
- public Object _call(JS.Array args) {
- if (args.length() == 1) return ((String)o).substring(toNumber(args.elementAt(0)).intValue());
- else if (args.length() == 2) return ((String)o).substring(toNumber(args.elementAt(0)).intValue(),
- toNumber(args.elementAt(1)).intValue());
- else throw new Error("String.substring() can only take one or two arguments");
- }
- };
- else if (v.equals("toLowerCase")) return new JS.Function() {
- public Object _call(JS.Array args) {
- return ((String)o).toLowerCase();
- } };
- else if (v.equals("toUpperCase")) return new JS.Function() {
- public Object _call(JS.Array args) {
- return ((String)o).toString().toUpperCase();
- } };
- else if (v.equals("charAt")) return new JS.Function() {
- public Object _call(JS.Array args) {
- return ((String)o).charAt(toNumber(args.elementAt(0)).intValue()) + "";
- } };
- else if (v.equals("lastIndexOf")) return new JS.Function() {
- public Object _call(JS.Array args) {
- if (args.length() != 1) return null;
- return new Integer(((String)o).lastIndexOf(args.elementAt(0).toString()));
- } };
- else if (v.equals("indexOf")) return new JS.Function() {
- public Object _call(JS.Array args) {
- if (args.length() != 1) return null;
- return new Integer(((String)o).indexOf(args.elementAt(0).toString()));
- } };
- throw new Error("Not Implemented: propery " + v + " on String objects");
- } else if (o instanceof Boolean) {
- throw new Error("Not Implemented: properties on Boolean objects");
- } else if (o instanceof Number) {
- Log.log(this, "Not Implemented: properties on Number objects");
- return null;
- //throw new Error("Not Implemented: properties on Number objects");
- } else if (o instanceof JS) {
- return ((JS)o).get(v);
+ case LB: {
+ b.add(b.EXPR, prefix);
+ b.add(b.EXPR, startExpr());
+ consume(RB);
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ b.add(b.EXPR, startExpr());
+ b.add(b.PUT);
+ b.add(b.SWAP);
+ b.add(b.POP);
+ } else {
+ b.add(b.GET);
}
- return null;
+ return continueExpr(b, minPrecedence);
}
- }
- class Thread {
- public Object[] os = new Object[256];
- private int size = 0;
- public void push(Object o) {
- os[size++] = o;
- }
- public Object pop() {
- return os[--size];
+ case HOOK: {
+ b.add(b.EXPR, prefix);
+ b.add(b.JF, new Integer(3));
+ b.add(b.EXPR, startExpr());
+ b.add(b.JMP, new Integer(2));
+ consume(COLON);
+ b.add(b.EXPR, startExpr());
+ return continueExpr(b, minPrecedence);
}
- public Object peek() { return os[size - 1]; }
- public void swap() { Object temp = os[size - 1]; os[size - 1] = os[size - 2]; os[size - 2] = temp; }
- public int size() { return size; }
- }
-
- class ExprList extends Expr {
- Vec v = new Vec();
- public ExprList(int curLine, int code) { super(curLine, code); }
- public void add(Expr e) { v.addElement(e); }
- public int numExprs() { return v.size(); }
- public int size() { return v.size(); }
- public Expr elementAt(int i) { return (Expr)v.elementAt(i); }
- public Object eval(final JS.Scope s) throws ControlTransferException, JS.Exn {
- switch(code) {
- case LC: {
- // Block
- JS.Scope scope = new JS.Scope(s);
- for(int i=0; i<v.size(); i++) ((Expr)v.elementAt(i)).eval(scope);
- return null;
- }
- case Lexer.LB: {
- // Array ctor
- JS.Array ret = new JS.Array();
- for(int i=0; i<numExprs(); i++) ret.addElement(elementAt(i).eval(s));
- return ret;
- }
- case Lexer.RC: {
- // Object ctor
- JS.Obj ret = new JS.Obj();
- for(int i=0; i<numExprs(); i++) {
- Expr e = elementAt(i);
- Object key = e.left.string;
- Object val = e.right.eval(s);
- ret.put(key, val);
- }
- return ret;
- }
- case Lexer.WHILE:
- case Lexer.DO:
- try {
- boolean first = true;
- Object bogus = null;
- ExprList list = this;
- Expr whileExpr = list.elementAt(0);
- Expr bodyExpr = list.elementAt(1);
- Expr incExpr = list.elementAt(2);
- for(;(first && code == Lexer.DO) || toBoolean(whileExpr.eval(s)); bogus = incExpr.eval(s)) {
- first = false;
- try {
- bodyExpr.eval(s);
- } catch (ContinueException c) {
- if (c.label == null || c.label.equals(string)) continue;
- } catch (BreakException b) {
- if (b.label == null || b.label.equals(string)) return null;
- throw (BreakException)b.fillInStackTrace();
- }
- }
- } catch (BreakException e) {
- if (e.label != null && !e.label.equals(string)) throw e;
- }
- return null;
- case Lexer.VAR:
- for(int i=0; i<size(); i++) {
- Expr e = elementAt(i);
- s.declare(e.left.string);
- if (e.right != null) e.right.eval(s);
- }
- return null;
- default: throw new Error("augh!");
- }
+
+
+ default: pushBackToken(); return prefix;
}
}
/** a block is either a single statement or a list of statements surrounded by curly braces; all expressions are also statements */
- public Expr parseBlock(boolean requireBraces) throws IOException { return parseBlock(requireBraces, null); }
- public Expr parseBlock(boolean requireBraces, ByteCode b) throws IOException {
- Expr smt = null;
+ public ForthBlock parseStatement() throws IOException {
+ ForthBlock ret = new ForthBlock(line, sourceName);
+ ret.add(ret.LITERAL, null);
+ parseStatement(false, ret);
+ if (ret.size() == 1) return null;
+ return ret;
+ }
+
+ public void parseStatement(boolean requireBraces) throws IOException {
+ parseStatement(requireBraces, new ForthBlock(line, sourceName));
+ }
+ public void parseStatement(boolean requireBraces, ForthBlock b) throws IOException {
int tok = peekToken();
- if (tok == -1) return null;
+ if (tok == -1) return;
boolean braced = tok == LC;
if (requireBraces && !braced) throw new ParserException("expected {, got " + codeToString[tok]);
if (braced) consume(LC);
int curLine = line;
- ByteCode ret = new ByteCode(curLine);
- ByteCode block = b == null ? new ByteCode(curLine) : b;
- block.add(ret.LITERAL, Boolean.TRUE);
- ret.add(block.SCOPE, block);
while(true) {
switch(tok = peekToken()) {
- case LC:
- smt = parseBlock(true); break;
-
- case THROW: case RETURN: case ASSERT:
+ case THROW: case RETURN: case ASSERT: {
getToken();
- if (peekToken() == SEMI) {
- if (tok == THROW || tok == ASSERT) throw new ParserException(codeToString[tok] + " requires an argument");
- consume(SEMI);
- smt = new Expr(curLine, tok);
- } else {
- smt = new Expr(curLine, tok, parseMaximalExpr());
- consume(SEMI);
- }
+ if (tok == RETURN && peekToken() == SEMI) b.add(b.LITERAL, null);
+ else b.add(b.EXPR, startExpr());
+ consume(SEMI);
+ b.add(tok);
break;
+ }
- case GOTO: case BREAK: case CONTINUE: {
+ case BREAK: case CONTINUE: {
getToken();
- int t = peekToken();
- if (t == NAME) {
- getToken();
- smt = new Expr(curLine, tok, new Expr(curLine, string));
- } else if (tok == GOTO) {
- throw new ParserException("goto must be followed by a label");
- }
- smt = new Expr(curLine, tok, new Expr(curLine, string));
+ if (peekToken() == NAME) consume(NAME);
+ b.add(tok, string);
consume(SEMI);
break;
}
- case RC:
- if (braced) consume(RC);
- return block.size() == 0 ? null : ret;
-
case SEMI:
consume(SEMI);
- if (!braced) return block.size() == 0 ? null : ret;
- continue;
+ if (!braced) return;
+ break;
- case NAME: {
- String name = string;
- consume(NAME);
- if (peekToken() == COLON) {
- consume(COLON);
- smt = new Expr(curLine, COLON, new Expr(curLine, name), parseBlock(false));
- break;
- } else {
- pushBackToken(NAME, name);
- // fall through to default case
+ case VAR: {
+ consume(VAR);
+ b.add(THIS); // push the current scope
+ while(true) {
+ consume(NAME);
+ String name = string;
+ b.add(b.LITERAL, name); // push the name to be declared
+ b.add(b.DECLARE); // declare it
+ if (peekToken() == ASSIGN) { // if there is an '=' after the variable name
+ b.add(b.LITERAL, name); // put the var name back on the stack
+ consume(ASSIGN);
+ b.add(b.EXPR, startExpr());
+ b.add(b.PUT);
+ b.add(b.POP);
+ }
+ if (peekToken() != COMMA) break;
+ consume(COMMA);
}
+ b.add(b.POP);
+ if (peekToken() == SEMI) consume(SEMI);
+ break;
}
-
- case -1:
- default:
- smt = parseMaximalExpr();
- if (smt == null) return block.size() == 0 ? null : ret;
- if (peekToken() == SEMI) getToken();
+
+ case IF: {
+ consume(IF);
+ consume(LP);
+ b.add(b.EXPR, startExpr());
+ consume(RP);
+ b.add(b.JF, new Integer(4));
+ b.add(b.EXPR, parseStatement());
+ b.add(b.POP);
+ b.add(b.JMP, new Integer(3));
+ if (peekToken() == ELSE) {
+ consume(ELSE);
+ b.add(b.EXPR, parseStatement());
+ b.add(b.POP);
+ } else {
+ b.add(b.JMP, new Integer(1)); // nop
+ b.add(b.JMP, new Integer(1)); // nop
+ }
break;
}
- if (!braced) return smt;
- block.add(block.EXPR, smt);
- block.add(block.POP, NO_ARG);
- }
- }
-
-
- /** sorta like gcc trees */
- class Expr {
- int code = -1;
-
- final Expr left;
- final Expr right;
- int line = -1;
- String sourceName = "unknown";
-
- String string = null;
- Number number = null;
-
- public String toString() { return toString(0); }
- public String toString(int indent) {
- String ret = "";
- for(int i=0; i<indent; i++) ret += " ";
- ret += Lexer.codeToString[code];
- if (code == Lexer.NUMBER) ret += " " + number;
- else if (string != null) ret += " \"" + string + "\"";
- ret += "\n";
- if (left != null) ret += left.toString(indent + 2);
- if (right != null) ret += right.toString(indent + 2);
- return ret;
- }
-
- public Expr(int line, String s) { this(line, Lexer.STRING); this.string = s; } // an identifier or label
- public Expr(int line, int code, String s) { this(line, code); this.string = s; }
- public Expr(int line, Number n) { this(line, Lexer.NUMBER); this.number = n; } // an identifier or label
- public Expr(int line, int code) { this(line, code, null, null); }
- public Expr(int line, int code, Expr left) { this(line, code, left, null); }
- public Expr(int line, int code, Expr left, Expr right) {
- this.code = code; this.left = left; this.right = right;
- this.line = line;
- this.sourceName = Parser.this.sourceName;
- }
-
- public double toDouble(Object o) { return toNumber(o).doubleValue(); }
- public long toLong(Object o) { return toNumber(o).longValue(); }
- public boolean toBoolean(Object o) {
- if (o == null) return false;
- if (o instanceof Boolean) return ((Boolean)o).booleanValue();
- if (o instanceof Number) return o.equals(new Integer(0));
- return true;
- }
-
- public Object eval(final JS.Scope s) throws ControlTransferException, JS.Exn {
- switch(code) {
-
- case Lexer.NULL: return null;
- case Lexer.TYPEOF: {
- Object o = left.eval(s);
- if (o == null) return "null";
- if (o.getClass() == String.class) return "string";
- if (o.getClass() == Boolean.class) return "boolean";
- if (o instanceof Number) return "number";
- if (o instanceof JS.Array) return "array";
- if (o instanceof JS) return "object";
- throw new EvaluatorException("typeof " + o.getClass().getName() + " unknown");
+ case WHILE: {
+ consume(WHILE);
+ consume(LP);
+ ForthBlock loop = new ForthBlock(curLine, sourceName);
+ b.add(loop.LOOP, loop);
+
+ loop.add(loop.POP);
+ loop.add(loop.EXPR, startExpr());
+ loop.add(loop.JT, new Integer(2));
+ loop.add(Lexer.BREAK);
+ consume(RP);
+ parseStatement(false, loop);
+
+ // if we fall out of the end, definately continue
+ loop.add(CONTINUE);
+ break;
}
- case Lexer.THROW: throw new JS.Exn(left.eval(s));
-
- case Lexer.TRY: {
- boolean safeToExit = false;
- try {
- Object ret = left.eval(s);
- safeToExit = true;
- return ret;
- } catch (JS.Exn e) {
- ExprList list = (ExprList)right;
- Expr c = list.elementAt(0);
- if (c.code == Lexer.CATCH) {
- JS.Scope scope = new JS.Scope(s);
- s.put(c.left.string, e);
- c.right.eval(scope);
- c = list.elementAt(1);
+ case SWITCH: {
+ consume(SWITCH);
+ consume(LP);
+ ForthBlock loop = new ForthBlock(curLine, sourceName);
+ b.add(loop.LOOP, loop);
+ loop.add(loop.EXPR, startExpr());
+ consume(RP);
+ consume(LC);
+ while(true) {
+ ForthBlock caseForthBlock;
+ tok = getToken();
+ if (tok == CASE) {
+ loop.add(loop.DUP);
+ loop.add(loop.EXPR, startExpr());
+ loop.add(EQ);
+ loop.add(loop.JF, new Integer(2));
+ } else if (tok != DEFAULT) throw new ParserException("expected CASE or DEFAULT");
+ consume(COLON);
+ ForthBlock b2 = new ForthBlock(curLine, sourceName);
+ ForthBlock e1 = null;
+ while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
+ if ((e1 = parseStatement()) == null) break;
+ b2.add(b.EXPR, e1);
+ b2.add(b.POP);
}
- if (c.code == Lexer.FINALLY) {
- JS.Scope scope = new JS.Scope(s);
- c.left.eval(scope);
+ loop.add(loop.EXPR, b2);
+ if (peekToken() == RC) {
+ consume(RC);
+ loop.add(BREAK);
+ break;
}
- } finally {
- if (!safeToExit) Log.log(this, "WARNING: Java exception penetrated a JavaScript try{} block");
}
- return null;
+ break;
}
-
- case Lexer.FOR:
- Object[] keys = ((JS)left.right.eval(s)).keys();
- for(int i=0; i<keys.length; i++) {
- JS.Scope scope = new JS.Scope(s);
- scope.declare(left.string);
- scope.put(left.string, keys[i]);
- try {
- right.eval(scope);
- } catch (ContinueException c) {
- if (c.label == null || c.label.equals(string)) continue;
- } catch (BreakException b) {
- if (b.label == null || b.label.equals(string)) return null;
- throw (BreakException)b.fillInStackTrace();
- }
+
+ case DO: {
+ consume(DO);
+ ForthBlock loop = new ForthBlock(curLine, sourceName);
+ b.add(loop.LOOP, loop);
+
+ parseStatement(false, loop);
+ consume(WHILE);
+ consume(LP);
+ loop.add(loop.EXPR, startExpr());
+ loop.add(loop.JT, new Integer(2));
+ loop.add(Lexer.BREAK);
+ loop.add(Lexer.CONTINUE);
+ consume(RP);
+ consume(SEMI);
+ break;
+ }
+
+ case TRY: {
+ // FIXME: don't just ignore this!
+ // We deliberately allow you to omit braces in catch{}/finally{} if they are single statements...
+ consume(TRY);
+ parseStatement(true, b);
+
+ if (peekToken() == CATCH) {
+ getToken();
+ consume(LP);
+ consume(NAME);
+ consume(RP);
+ parseStatement(); // just discard the catchblock
}
- return null;
- case Lexer.SWITCH:
- Object switchVal = left.eval(s);
- boolean go = false;
- try {
- ExprList list = (ExprList)right;
- for(int i=0; i<list.size(); i++) {
- Expr e = list.elementAt(i);
- if (go || e.code == Lexer.DEFAULT || e.left.eval(s).equals(switchVal)) go = true;
- if (go) e.right.eval(s);
- }
- } catch (BreakException b) {
- if (b.label == null || b.label.equals(string)) return null;
- throw (BreakException)b.fillInStackTrace();
+ if (peekToken() == FINALLY) {
+ consume(FINALLY);
+ parseStatement(false, b);
}
- return null;
+ break;
+ }
- case Lexer.BREAK: throw new BreakException(string);
- case Lexer.CONTINUE: throw new ContinueException(string);
- case Lexer.RETURN: throw new ReturnException(left == null ? null : left.eval(s));
+ case FOR: {
+ consume(FOR);
+ consume(LP);
- default: throw new EvaluatorException("don't know how to eval an Expr with code " + Lexer.codeToString[code] + "\n" + this);
- }
- }
+ tok = getToken();
+ if (tok == VAR) tok = getToken();
+ String varName = string;
+ boolean forIn = peekToken() == IN;
+ pushBackToken(tok, varName);
- class EvaluatorException extends RuntimeException {
- public EvaluatorException(String s) { super(sourceName + ":" + line + " " + s); }
- }
- }
+ if (forIn) {
+ consume(NAME);
+ consume(IN);
+ b.add(b.EXPR, startExpr());
+ b.add(b.PUSHKEYS);
+ b.add(b.LITERAL, "length");
+ b.add(b.GET);
+ consume(RP);
+ ForthBlock b2 = new ForthBlock(curLine, sourceName);
+ b.add(b.SCOPE, b2);
+ b2.add(b.LITERAL, new Integer(1));
+ b2.add(SUB);
+ b2.add(b.DUP);
+ b2.add(b.LITERAL, new Integer(0));
+ b2.add(LT);
+ b2.add(b.JT, new Integer(7));
+ b2.add(b.GET_PRESERVE);
+ b2.add(b.LITERAL, varName);
+ b2.add(b.LITERAL, varName);
+ b2.add(b.DECLARE);
+ b2.add(b.PUT);
+ b2.add(b.EXPR, parseStatement());
+ //b2.add(b.LITERAL, null);
+ break;
+
+ } else {
+ ForthBlock b2 = new ForthBlock(curLine, sourceName);
+ b.add(b.SCOPE, b2);
+ b.add(b.POP);
- static abstract class ControlTransferException extends Exception { }
- static class BreakException extends ControlTransferException {
- public String label;
- BreakException(String label) { this.label = label; }
- }
- static class ContinueException extends ControlTransferException {
- public String label;
- ContinueException(String label) { this.label = label; }
+ ForthBlock e1 = startExpr();
+ if (e1 == null) e1 = new ForthBlock(curLine, sourceName, b.LITERAL, null);
+
+ b2.add(b.EXPR, e1);
+ b2.add(b.POP);
+ consume(SEMI);
+ ForthBlock e2 = startExpr();
+ consume(SEMI);
+ ForthBlock e3 = startExpr();
+ consume(RP);
+
+ if (e2 == null) e2 = new ForthBlock(curLine, sourceName, b.LITERAL, null);
+ if (e3 == null) e3 = new ForthBlock(curLine, sourceName, b.LITERAL, null);
+
+ ForthBlock b3 = new ForthBlock(curLine, sourceName);
+ b2.add(b.LOOP, b3);
+ b2.add(b.LITERAL, null);
+ b3.add(b.JT, new Integer(3));
+ b3.add(b.EXPR, e3);
+ b3.add(b.POP);
+ b3.add(b.EXPR, e2);
+ b3.add(b.JT, new Integer(2));
+ b3.add(BREAK);
+ parseStatement(false, b3);
+ b3.add(BREAK);
+ break;
+ }
}
- static class ReturnException extends ControlTransferException {
- public Object retval;
- ReturnException(Object retval) { this.retval = retval; }
+
+ case NAME: {
+ consume(NAME);
+ String name = string;
+ if (peekToken() == COLON) {
+ consume(COLON);
+ b.add(ForthBlock.LABEL, string);
+ break;
+ } else {
+ pushBackToken(NAME, name);
+ // fall through to default case
+ }
+ }
+ // fall through
+ case RC:
+ if (tok == RC && braced) { consume(RC); return; }
+ // fall through
+ default: {
+ ForthBlock ret = startExpr();
+ if (ret == null) return;
+ b.add(b.EXPR, ret);
+ b.add(b.POP);
+ if (peekToken() == SEMI) consume(SEMI);
+ break;
+ }
+ }
+
+ if (!braced) return;
}
-
+ }
+
class ParserException extends RuntimeException {
public ParserException(String s) { super(sourceName + ":" + line + " " + s); }
}
-
- public static Number toNumber(Object o) {
- if (o == null) return new Long(0);
- if (o instanceof Number) return ((Number)o);
- if (o instanceof String) try { return new Double((String)o); } catch (NumberFormatException e) { return new Double(0); }
- if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? new Long(1) : new Long(0);
- if (o instanceof JS) return ((JS)o).coerceToNumber();
- // FIXME
- throw new Error("toNumber() got object of type " + o.getClass().getName());
- }
- }
+
+}
projects / org.ibex.core.git / blobdiff